1. Field of the Invention
This invention relates generally to a system and method for gas turbine rotor and exhaust maintenance and, more particularly, to a system and method for disassembling and reassembling a unified rotor and single piece exhaust assembly by providing a gas turbine rotor and exhaust assembly maintenance skid system that includes movable stands that allow the exhaust portion to be removed from the rotor and rollers that allow the rotor to be turned.
2. Discussion of the Related Art
The world's energy needs continue to rise which provides a demand for reliable, affordable, efficient and environmentally-compatible power generation. A gas turbine engine is one known machine that provides efficient power, and common applications are an electric generator in a power plant or engines for aircraft and ships. A typical gas turbine engine includes a compressor section, a combustion section and a turbine section. The compressor section provides a compressed air flow to the combustion section where the air is mixed with a fuel, such as natural gas, and ignited to create a hot working gas. The working gas expands through the turbine section and is directed across rows of blades therein by associated vanes. As the working gas passes through the turbine section, it causes the blades to rotate, which in turn causes a shaft to rotate, thereby providing mechanical work.
The temperature of the working gas is tightly controlled so that it does not exceed some predetermined temperature for a particular turbine engine design because too high of a temperature can damage various parts and components in the turbine section of the engine. However, it is desirable to allow the temperature of the working gas to be as high as possible because the higher the temperature of the working gas, the faster the flow of the gas, which results in a more efficient operation of the engine.
A single piece exhaust (SPEX) for a gas turbine engine has been in production for several years for certain types of turbine engines. Previous configurations included a horizontally split exhaust cylinder that allowed for the removal of the rotor of the turbine engine separate from the removal of the exhaust cylinder. With the SPEX design, the rotor and SPEX are removed together as an assembly. The rotor and SPEX may need to be removed for various reasons, including major inspections and/or repairs. The estimated size of a crane that is necessary to lift the rotor and SPEX assembly ranges from 550 to 650 ton, and possibly as high as 800 ton, depending on the site arrangement. Rental rates for such cranes may be in the range of $13,500 per day to $18,700 per day. The personnel cost for a typical major inspection when using a crane is approximately $70,000 per day. Because of the cost and time investment with using a crane to support the rotor and SPEX assembly during an inspection and/or repairs, there is a need in the art to be able to perform disassembly and reassembly of a rotor and SPEX assembly in a more cost effective manner.